package com.qiyu.security.handler;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.qiyu.common.R;
import com.qiyu.common.RStatus;
import com.qiyu.security.bean.JwtToken;
import com.qiyu.security.util.JwtUtil;
import lombok.extern.slf4j.Slf4j;
import org.apache.shiro.web.filter.authc.BasicHttpAuthenticationFilter;
import org.apache.shiro.web.util.WebUtils;
import org.springframework.http.HttpStatus;
import org.springframework.util.StringUtils;
import org.springframework.web.bind.annotation.RequestMethod;

import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.concurrent.TimeUnit;

@Slf4j
public class JwtFilter extends BasicHttpAuthenticationFilter {
    
    private static final ObjectMapper OBJECT_MAPPER = new ObjectMapper();
    
    /**
     * 执行登录认证
     *
     * @param request
     * @param response
     * @param mappedValue
     * @return
     */
    @Override
    protected boolean isAccessAllowed(ServletRequest request, ServletResponse response, Object mappedValue) {
        try {
            executeLogin(request, response);
            return true;
        } catch (Exception e) {
            String message = null;
            try {
                message = OBJECT_MAPPER.writeValueAsString(R.error(RStatus.NO_LOGIN.getValue(), e.getMessage(), null));
            } catch (JsonProcessingException ignored) {
            }
            response401(response, message);
            return false;
        }
    }
    
    @Override
    protected boolean executeLogin(ServletRequest request, ServletResponse response) {
        HttpServletRequest httpServletRequest = (HttpServletRequest) request;
        String token = getToken(httpServletRequest);
        
        JwtToken jwtToken = new JwtToken(token);
        // 提交给realm进行登入，如果错误他会抛出异常并被捕获
        getSubject(request, response).login(jwtToken);
        // 如果没有抛出异常则代表登入成功，返回true
        
        //设置用户ID
        String userId = JwtUtil.getUserId(token);
        httpServletRequest.setAttribute("userId", userId);
        return true;
    }
    
    
    /**
     * 对跨域提供支持
     */
    @Override
    protected boolean preHandle(ServletRequest request, ServletResponse response) throws Exception {
        HttpServletRequest httpServletRequest = (HttpServletRequest) request;
        HttpServletResponse httpServletResponse = (HttpServletResponse) response;
        httpServletResponse.setHeader("Access-control-Allow-Origin", httpServletRequest.getHeader("Origin"));
        httpServletResponse.setHeader("Access-Control-Allow-Methods", "GET,POST,OPTIONS,PUT,DELETE");
        httpServletResponse.setHeader("Access-Control-Allow-Headers", httpServletRequest.getHeader("Access-Control-Request-Headers"));
        //option请求多久校验一次，前端缓存校验
        httpServletResponse.setHeader("Access-Control-Max-Age", String.valueOf(TimeUnit.DAYS.toSeconds(1)));
        // 跨域时会首先发送一个option请求，这里我们给option请求直接返回正常状态
        if (httpServletRequest.getMethod().equals(RequestMethod.OPTIONS.name())) {
            httpServletResponse.setStatus(HttpStatus.OK.value());
            return false;
        }
        return super.preHandle(request, response);
    }
    
    /**
     * 获取token
     */
    private String getToken(HttpServletRequest request) {
        String token = request.getHeader("token");
        if (StringUtils.isEmpty(token)) {
            token = request.getHeader("Authorization");
        }
        if (StringUtils.isEmpty(token)) {
            token = request.getHeader("authorization");
        }
        return token;
    }
    
    /**
     * 返回认证失败信息
     */
    private void response401(ServletResponse response, String msg) {
        HttpServletResponse httpServletResponse = WebUtils.toHttp(response);
        httpServletResponse.setStatus(HttpStatus.UNAUTHORIZED.value());
        httpServletResponse.setCharacterEncoding("UTF-8");
        httpServletResponse.setContentType("application/json; charset=utf-8");
        try (PrintWriter out = httpServletResponse.getWriter()) {
            out.append(msg);
        } catch (IOException e) {
            log.error("直接返回Response信息出现IOException异常:{}", e.getMessage());
        }
    }
}
